1. Field of the Invention
This invention relates to and is useful for respiratory therapy. More particularly, the present invention involves a percussion instrument which is repeatedly struck against or applied to the chest wall of a human individual for the purpose of delivering sound waves or percussion to the lung area. The percussion effects aid in loosening trapped secretions (characteristic of many chronic lung diseases such as asthma, cystric fibrosis, and emphysema), and in re-expanding collapsed airways (treating atelectasis). The technique is particularly useful to deliver percussion to the chest wall of premature infants and small children suffering from acute an chronic lung disorders, where atelectasis, trapped and/or excessive lung secretions are a problem. The technique is technically termed chest physiotherapy and is usually used in conjunction with postural drainage and vibration techniques.
2. Introduction and Brief Description of Prior Art
Historically, the first percussion devices used for respiratory therapy were the human hands. The hand of the therapist is cupped with the fingers and thumb closed to trap a pocket or cushion of air between the hand and chest wall as the cupped hand repeatedly struck the patient's bare chest. When properly executed, a clapping, hollow sound results and the percussion or sound vibrations are conducted deeply into the lung field. It is only with considerable experience and skill that the cupped hand technique is properly executed.
The cupped hand technique, if properly executed, is a reasonably satisfactory execution of respiratory therapy for adults. However, for small children, particularly premature infants whose weight may not exceed 1000 grams, the hand technique is inappropriate because the therapist's hands may be considerably larger than the infant's chest. Of course, with adults the therapist's hand is small in comparison with the chest wall.
To overcome the problem of improperly executing the cupped hand technique and the problem of applying respiratory therapy or chest physiotherapy to very small human individuals, various percussion instruments have been devised. One such device is a percussion hammer which employs a soft rubber cup at one end of an electrically driven reciprocating shaft. Percussion hammers avoid many of the problems in executing the cupped hand technique, but the heavy mechanical percussion hammers are too dangerous to use on infants and small children. Consequently hand-held, manually-operated percussion instruments are useful on infants and small children.
Most manually operated instruments have been makeshift in nature, and a new instrument had to be contrived for each instance of respiratory therapy. One example of a contrived percussion instrument is a small infant breathing mask which is oval in shape with cushions attached on the edges of the mask. Other examples are a small plastic medication cup or ear bulb syringe with an end cut off, both having tape wrapped around the edges.
Problems have resulted because of the makeshift nature of certain prior art percussion instruments. Generally the percussion instruments lack an adequate cushion to prevent injury to the skin as the instrument is repeatedly struck against the chest wall. Incidents of severe bruises and bleeding have been known to occur. Another problem is that most percussion instruments do not adequately seal against the chest wall. With an inadequate seal, the sound wave percussion effects are not propigated deep into the lung field, and effective chest physiotherapy is lost. A futher deficiency is that an interior chamber is not arranged for most effectively conducting the sound wave percussion deep into the lung area. The typical prior art configuration of the interior chamber often causes the sound waves to bounce between the walls of the interior chamber, thereby dissipating the energy effect of the waves instead of projecting the energy into the lung areas. Lastly, many prior art percussion instruments are not formed with an exterior configuration that can be readily grasped by the therapist. Without good control over the percussion instrument, which often occurs due to slippery surfaces and the like, the therapist cannot create a percussion effect at regular intervals. Consequently, effect of the therapy treatment is comprised. According to Eagan, Fundamentals of Respiratory Therapy, page 444, it is essential to the practice of chest percussion "to maintain a uniform blow throughout the entire procedure." The ability to adequately grip the percussion instrument to maintain uniform percussion effects at regular intervals is even more significant when very small percussion instruments are employed, since the small size of the percussion instrument is more difficult to grasp in the large hand of an adult.
Other disadvantages and limitations of the prior art are known. Those skilled in the art may recognize still further limitations and disadvantages in view of the desirable aspects to the present invention, but comprehension of the desirable aspects of this invention should not diminish the significance of many of the previous troublesome limitations in the prior art. Examples of prior art massage type devices are U.S. Pat. Nos. 728,003; 793,527; 915,251; 1,198,176; 1,201,767; and 2,078,536.